فصلنامه پژوهش های تولید گیاهی
سال بیست و هشتم شماره 4 (زمستان 1400)

Medicinal plants play an important role in human health in the world. Many people in different countries of the world tend to use these drugs. Therefore, improve quality of natural medicinal plants is an absolute necessity. Intercropping using time and space, in addition of improving plant production methods in terms of environmental and human health, can increase agricultural production, also. Considering the mentioned issues and the management of weeds in agricultural landscapes, which is one of the biggest problems faced by farmers, this experiment was aim of investigation biochemical characteristics and yield of savory (Satureja hortensis L.) and fenugreek (Trigonella foenum- greacum L.) in intercropping with weeds competition and non- competition conditions.

This experiment was carried out as a split plot in randomized complete block design with three replications in Research Farm of Sari Agricultural Sciences and Natural Resources University in 2016. The treatments of this experiment consisted weeding and no-weeding as the main factor and also, monoculture of savory, monoculture of fenugreek, ratio of 75:25, 50:50 and 25:75% (savory and fenugreek) as sub plots. Dominant weeds were identified as velvetleaf (Abutilon theophrassti Medic.), giant foxtail (Setaria glauca L.), wild melon (Cucumis melo var. agrestis), and bermuda grass (Cynodon dactylon). The studied traits included: shoot fresh and dry weight of savory and fenugreek, photosynthetic pigments (chlorophyll a, b and total chlorophyll), total phenol, total flavonoids, antioxidant activity of them and weeds biomass.

The simple effect of experimental treatments was significant on photosynthetic pigments savory and fenugreek. Phenolic and flavonoid content of leaf and antioxidant capacity for both plants were maximum in 50% savory: 50% fenugreek ratio in weed infestation and showed significant increament in weed infestation compare to weed free. Monoculture of savory showed maximum fresh (1586.67 and 1813.33 g m-2, respectively) and dry (842.33 and 649.20 g m-2, respectively) weight of shoot in weed controlled conditions. The results of the data analysis showed that in all of the three sampling, the highest and lowest biomass of weed species was related to the pure stand of savory and the ratio of 25:75% of savory: fenugreek, and the highest weed biomass was observed in the second stage of sampling.

Overall, the results showed that the intercropping of savory and fenugreek could stabilize the production and betterment biochemical characteristics by improving the use of resources. In addition by decreasing weeds dry weight reduces weed damage and as well as reducing herbicide use, consequently, it is effective for the sustainable production of medicinal plants.

Salinity is an agricultural problem of great concern, at which, about one third of the world’s irrigated land is not in use. Several microorganisms such as fluorescent Pseudomonas, known to have the ability to tolerate high salt concentrations. Among these microorganisms, Pseudomonas fluorescens is plant growth promoting rhizobacterium and lives in the plant rhizosphere. This study was executed to evaluate the impact of Pseudomonas fluorescens on growth parameters and some biochemical constituents related to salinity in safflower (Carthamus tinctorius L.) Arak 12811 cultivar under salt stress.

Treatments, four levels salinity stress factor with sodium chloride salt (0, 5, 25, 50 and 150 mM) and two level inoculation factor (control and bacterium) as a factorial experiment in a completely randomized design with four replications was designed. Safflower seeds coated with growth promoting bacteria with 5% cellulose carboxymethyl and the plants grow in pots under different salt levels. After 40 days, root and shoot dry weight and relative water content measured under salt levels and bacterial inoculations. Also changes of chlorophyll a and b, carotenoides, proline, soluble sugars, glycine betaine and malondialdehyde contents were measured by chlorometric analysis.

The results showed that an increase in NaCl concentration in the nutrient solution reduced the height, shoot and root dry weight and chlorophyll a and b content in soybean plants while the amount of proline, soluble sugars, glycine betaine and malondialdehyde, increased. Safflower plants inoculated with P. fluorescens gave the highest significant increment in plant height, stem and root dry weights, chlorophyll a and b, carotenoides and relative water content under saline and non-saline conditions. Negative correlation between relative water content and total soluble sugars, glycine betaine and proline, show osmolytes accumulation for continued water uptake and reduced osmotic stress. The highest significant activity of proline, total soluble sugars and glycine betaine were recorded with inoculated plants irrigated with 150 mM NaCl solution. The bacterium inhibited malondialdehyde accumulation and decreased lipid peroxidation. Overall, this research revealed that seedlings inoculated with promoting growth bacterium until 50 mM salinity has provided most optimal performance and efficiency.

The present results revealed increases in safflower plant growth and biochemical constituents related to salinity by using of P. fluorescens, which could be suggested for improve plant salinity stress resistance.

As the world's population grows, demand for fruits is increasing day by day. Fruits are an important part of the human diet and their consumption guarantees human health and strawberries are of particular importance. Strawberries are high in fiber, vitamin C, potassium and antioxidants. Due to the high nutritional value of strawberry fruits and the expansion of hydroponic cultivation in the world, and in our country, it is important to pay attention to the plant nutrition. Optimal nutrition of the plant is one of the main strategies to achieve economic productivity. Since nutrient balance is essential for commercial fruit production, improving yield and fruit quality, so foliar application at key stages can have a positive effect on the quantitative and qualitative traits of perennial crops. Among essential minerals that are involved in plant physiology, micronutrients of zinc (Zn) and boron (B), because of their relation with synthetic hormones are particularly important. So according to the importance of micronutrients on horticultural yield improving and environmental protection, this investigation was conducted to evaluate the effect of foliar application of zinc and boron and combination of them on growth and yield of strawberry cultivar ʻAromas’ in hydroponic system.

A 3×3 factorial experiment, arranged in a randomized complete block design (RCBD) with nine replications, was conducted at the research greenhouse of Sari Agricultural Sciences and Natural Resources University in 2016 and 2017. Treatments were zinc sulfate (0, 100 and 200 mg l-1) and boric acid (0, 500 and 1000 mg l-1). Foliar application of the treatments was carried out in three stages. The first stage was carried out a week before the flowering and in the next steps, the treatments were sprayed on plants at intervals of two weeks. In this research, the effect of zinc and boron on the yield, root length, root diameter, chlorophyll index, crown diameter, total chlorophyll, chlorophyll a/b, specific leaf area, specific leaf weight, petiole diameter, leaf width, leaf length, leaf area, flowering time, flowering period, peduncle length, flower diameter, flower number, fruitification time, fruitification period, fruit number, percentage of fruit set, percentage of marketable fruits, percentage of non-marketable fruits, fruit length to diameter ratio (L/D), fruit dry weight, fruit volume and percentage of fruit dry matter were investigated.

Results showed that the application of 200 mg l-1 zinc sulfate plus 500 mg l-1 boric acid significantly increased the crown diameter. Application of zinc and boron sources significantly increased the chlorophyll concentration and index of ‘Aromas’ strawberry compared to the control treatment. The highest increases in specific leaf area (141.52 cm2g-1) were monitored in response to 100 mg l-1 zinc sulfate + 500 mg l-1 boric acid treatment. The application of zinc sulfate and boric acid significantly increased the number of flower, flowering period and number of fruit. However, by increasing the concentration of boric acid (from 500 to 1000 mg l-1) significantly reduced the number of fruit. Generally, application of 200 mg l-1 zinc sulfate plus 500 mg l-1 boric acid to achieve increased fruitification period (91.32 day) and yield (210.4 g) of ‘Aromas’ strawberry fruit is suggested.

In general, it can be concluded that foliar application of zinc and boron and combination of both them in most of the measured reproductive and vegetative factors, improved the parameters studied.Therefore, in order to achieve high yield and improve the growth traits of strawberry cultivar ʻAromas’ in hydroponic system, the results of this research can be applied.

Chickpea (Cicer arietinum L.) is one of the oldest of legume species that was identified in the Middle East about 7,500 years ago. This crop had an important role for human nutrition as source of protein, energy, fiber, vitamins, and minerals. Among the different agronomic practices, sowing time is the most important factor to achieving chickpea optimum yield. Chickpea Optimum sowing date is different from a cultivar to another and also from a region to another, due to agro-ecological conditions. Winter sowing is a kind of sowing date that is successful in terms of agronomic condition. In order to study of effect of different sowing dates on quantitative and qualitative yield of chickpea under dryland condition, an experiment was conducted.

This experiment was done at the Agricultural Research Station Faculty of Agriculture, University of Bu-Ali Sina, Hamedan, Iran (latitude 35◦1' N, longitude 48◦31' E and 1690 m altitude). The long-term average (30 years) of region air temperature is 12.5 ° C. The long-term average of air temperature during region growing season is 22˚C. The experiment was done during 2012 and 2013 growing seasons. Sowing dates in four level, including 10 January, 10 February, 10 March and 9 April of both years were as main plot, and three chickpea cultivar, including Hashem, Arman and Azad were as subplot. In this study was evaluated yield component, biological and grain yield, protein percent and protein yield and root nud number.

Results showed that the effect of year on chickpea experimental properties was not significant, but the all of the evaluated traits were affected by sowing dates significantly. The highest rates of total dry matter, grain protein percent, grain yield and protein yield (772.33 g m-2 and %25.85, 236.16 and 61.05 g m-2, respectively) was belonged to first sowing date (10 January) and Hashem cultivar. Also, the lowest total dry matter, grain protein percent, grain yield and protein yield (444.90 g m-2 and %22.17, 75.91 and 16.83 g m-2, respectively) was achieved at last sowing date (9 April) and Azad cultivar. The highest and lowest plant height, first sheath height, leaf area index and root nud number was achieved at the first sowing date (10 January) and final sowing date (9 April), respectively, that traits values at 10 January sowing date were significantly more than other sowing dates.

According to the results of this study, it can be concluded that the winter cropping of chickpea leads to improvement of growth properties and quantitative and qualitative yield of this crop, as by increasing of growth period leads to increasing of grain yield and total dry matter. According to the environmental conditions of the experiment site, the sowing date of 10 January, can be considered as the best sowing date.

The shortage of oilseeds and the high volume of oil imports in Iran and the limitation of water resources for the many oilseeds production, showed the necessity of identifying species and varieties adapted to these stressful conditions and determining the most sensitive stages. Nowadays, safflower, due to drought resistance, is considered as a plant crop in the Iranian crop rotation. Therefore, whith respect to importance of water stress and selection of appropriate planting date in crop production, this research was conducted to investigate the effect of delay cropping and irrigation regime on assimilate remobilization, yield components and yield safflower.

In order to investigate the effect of delay cropping and irrigation regime on assimilate remobilization rate, yield components and yield of safflower , a field experiment was conducted as split factorial in a completely randomized block design with three replicates at Agriculture College and Natural Resources of Darab, Shiraz University, during 2018-2019 growing season. Experimental factors consisted of irrigation regimes in three levels included normal irrigation, Cutting of irrigation at flowering and Cutting of irrigation at seed filling, three planting dates (6 December, 26 December and 15 January) and two safflower cultivars (Goldasht and local Isfahan). In this research, dry matter remobilization, remobilization contribution and remobilization efficiency, yield components and yield of safflower were determined.

Results showed that the measured traits were affected by irrigation regime, planting date and cultivar, significantly. Cutting of irrigation at flowering reduced number of capitule per plant, number of seeds per capitule, 1000-seed weight and grain yield of safflower cultivars by 21.86%, 23.87%, 28.37% and 33.74%, respectively compared to normal irrigation. The amount of dry matter remobilization, remobilization contribution and remobilization efficiency in cutting of irrigation at flowering increased 30.44%, 37.81% and 25.37%, respectively compared to normal irrigation. Also, delayed third planting date (15 January) reduced dry matter remobilization (44.17%), remobilization contribution (22.72%), remobilization efficiency (17.88%), number of capitule per plant (%). 14.57, number of seeds per capitule (20.65%) and grain yield (13.31%).

Cutting of irrigation at flowering and seed filling treatments decreased 52.32% and 34.54% of grain yield in Isfahan local cultivar at second planting date (26 December) compared to the normal irrigation treatment, respectively,. However, seed yield in this treatment did not differ significantly with the treatment of cutting of irrigation at seed filling in planting date on 6 December in Isfahan and Goldasht cultivars which seems to be due to increased assimilate remobilization and remobilization efficiency in cutting of irrigation at seed filling compared to normal irrigation. Therefore, selection of optimum planting date (26 December) compared to early planting date (6 December) and early mature Goldasht cultivar by 12.91% higher yield can be an appropriate strategy to improve and increase safflower seed yield under late season water stress in semi-arid regions.

Eco-lawn is a mixture of grass and broad leafy plants to create a diverse species composition. In fact, it is low input lawn that requires less watering, fertilizing, herbicide and mowing. It resists to invasion of weeds, which helps conserve natural resources and reduce pollutants.

This experiment was done in greenhouse at Ferdowsi university of Mashhad to explore the effects of water stress (85, 65, 45 and 25 % of FC) on shoot and root reactions of grass-clover mixtures. It was done in a factorial experiment based on randomized complete block design with three replications. Treatments were six mixtures of Festuca arundinacea and micro clover (FM), Lolium perenne and micro clover (LM), Lolium perenne and Trifolium repens (LT), F. arundinacea and L. perenne and micro clover (FLM), F. arundinacea, L. perenne, micro clover and T. repens (FLTM). Traits of height, leaf width, tiller number, fresh and dry weight of shoot and root, root surface, Mean diameter root, total root length, root volume were measured.

The results showed that in the competition between 6 types of mixed grass-clover, the highest and the lowest height were for LT mixed with mean of 5.89 cm and FLTM mixed with average of 5.02 respectively. In terms of fresh and dry weights of shoots, FLTM and LT had the highest and FM had the lowest production weight. Also 65% FC stress had no significant effect on plant height and significant difference was observed at 45 and 25% FC levels. The effect of 25% FC on leaf width and tiller number was significant and 45% FC of stress intensity had no significant effect on fresh and dry weight of aerial parts of grasses. In terms of underground organs, the highest fresh and dry weight of roots belonged to FLTM and LM and then FM. But the lowest fresh and dry weight of roots produced by LT grass with 38.68 and 9.52 gr/ pot respectively. In terms of different levels of drought stress, in mild stress of 65% FC, the amount of fresh and dry weight of roots increased compared to the level of 85% by 20.93% and 9.54%. But in 45% FC stress, drought stress led to a decrease in fresh and dry weight of root production. So that, in severe stress of 25% FC, in compared to 85% stress, the rate of fresh and dry root weight loss was 52.64 and 54.87%, respectively.

It can be concluded that all mixtures except LT were superior in root traits than commercial sport turf (S), while FLTM was the best blended especially for aerial parts traits than others.

Raspberry (Rubus idaeus L.) is most important small fruits in the world with a good color and taste. The potential for optimum off-season production under greenhouse conditions improved its commercial value. In-vitro tissue culture is one of the methods for large-scale and uniform propagation of raspberries, where the type and concentration of employed growth regulators are crucial to complement and accelerate growth. Therefore, the aim of this study was to investigate the effect of different concentrations of benzyladenine and indolebutyric acid on direct regeneration of the raspberry lateral bud.

Red raspberry bushes cv. September were used for this experiment. The experiment was carried out a factorial experiment in a completely randomized design with four replications and each replication with five explants at Sari University of Agricultural Sciences and Natural Resources. Uniform lateral bud explants after disinfection placed in culture medium containing benzyladenine at three levels of 0, 0.4 and 1 mg L-1 and indolebutyric acid at three levels of 0, 0.1 and 0.5 mg L-1 in controlled environmental conditions and finally traits such as leaf number, node number, root number, root length and ect as well as photosynthetic pigments were measured.

The results of this study showed that simultaneous use of different concentrations of benzyladenine and indolebutyric acid growth regulators in the culture medium of raspberry explants had a positive effect on a number of studied traits. The use of high concentrations of benzyladenine increased traits such as leaf number, number of node, number of internode, leaf length, lamina length. Also, the use of benzyladenine with high concentrations of indolebutyric acid increased explant size and petiole diameter. Examination of explant root length and number showed that increasing benzyl adenine concentration decreased these traits, but the use of indolebutyric acid at higher levels increased root length and number. Evaluation of the effect Results of benzyladenine and indolebutyric acid on photosynthetic pigments indicated that the increase of these regulators increased chlorophyll a, chlorophyll b and carotenoid in traeted explants.

In general, the use of benzyladenine plus indolebutyric acid was effective depending on the concentration used, was effective in improving the vegetative traits of the plantlets of the raspberry lateral bud explants, but indolebutyric acid alone only affected rooting at high concentrations. So that the use of indolebutyric acid increased root number and length at higher levels that suggesting a functional contrast between these two growth regulators. Investigating the effect results of benzyladenine and indolebutyric acid on photosynthetic pigments resolved the ambiguity of how enhancing these regulators led to synergized and improved explant size. It was observed that with increasing concentrations of these regulators, increased in important photosynthetic pigments such as chlorophyll a, chlorophyll b and carotenoid was obvious. Importantly, the tissue and organs of raspberries are more susceptible than black berry and respond to lower concentrations of this growth regulators.

Rootstocks can affect the reaction of the grafted trees to water stress by controlling vegetative growth and nutrients uptake and studying morpho-physiological and nutritional mechanisms and responses of the rootstocks submitted to drought stress would make it feasible to select the tolerant rootstocks. For this purpose, to investigate the effects of drought stress on some clonal Prunus sp. rootstocks, an experiment, in completely randomized design was conducted in a greenhouse in Saman (Sharekord) and Shahrekord University laboratories in 2017-2018.

Rooted cuttings of Cadaman, Myrobalan29c, GF677 and GN15 were planted and maintained under greenhouse conditions employing regular practices including irrigation and nutrients supplementation and pest management for three months. Plants were submitted to drought stress at three levels including 100, 75 and 50% of field capacity for 40 days. Plant height, dry weight, relative water content, water use efficiency, electrolyte leakage and mineral content (P, K+, Ca2+, Mg2+, Fe2+ and Zn2+) in leaves and roots were assessed.

The results showed that the total dry weight was significantly decreased under the influence of drought stress. Leaf moisture content and specific leaf weight (SLW) decreased but leaf area ratio (LAR) and specific leaf area (SLA) increased under water deficit condition. Also, due to the drought stress, the greatest decrease in growth rate occurred in Cadaman and Myrobalan29c rootstocks, but no significant changes were observed for GN15 rootstock. Under drought stress conditions, relative water content (RWC) of the leaves decreased, while electrolyte leakage (EL) increased, with the highest figures observed for Myrobalan29c. With the increasing intensity of drought stress, water use efficiency (WUE) decreased for the Cadaman rootstock, but it was increased for GF677 and GN15 rootstocks. While no significant changes were observed for Myrobalan29c rootstock. Drought stress reduced the mineral contents (P, K+, Ca2+ and Mg2+) in the roots and leaves of the rootstocks. The highest decrease in concentrations of elements such as K+, Ca2+, P and Fe2+ were found for Myrobalan29c and Cadaman rootstocks.

All the tested rootstocks were significantly affected by drought stress, including growth retardation, but they resisted to drought stress at different levels and by varying mechanisms. So that some rootstocks with better use of available water and more nutrients absorption efficiency, showed a greater ability to maintain their biological activities in the face of dehydration. Other rootstocks showed poorer performance against drought stress and underwent damages compared to other rootstocks.

The production and processing of medicinal plants is increasing day by day due to less side effects. The quality and quantity of medicinal plants are particularly affected by genetics, environmental factors and their interaction. Among natural limiting factors, water shortage is the most important factor that, especially in arid and semi-arid regions of the world, in various ways causes the restriction of planting and reduces the production of crops and medicinal plants. On the other hand, nutrients such as potassium can play an important role in plant resistance to environmental stresses. Therefore, this experiment was performed to investigate the effects of drought stress and potassium fertilizer on quantitative and qualitative characteristics and yield of German chamomile.

In order to investigate the effect of drought stress and different levels of potassium fertilizer on quantitative and qualitative characteristics of chamomile, a split plot experiment was conducted in a randomized complete block design with three replications in the Field of University Research Zabol. The treatments included drought stress in three levels, control (90% Field Capacity= FC), medium stress (70% FC), severe stress (50% FC) as the main factor and different levels of potassium sulfate fertilizer in four levels, non-consumption Potassium fertilizer (control), 50, 100 and 150 kg of potassium sulfate per hectare were considered as a sub-factor. The studied traits were as follows: plant height, number of stems, plant dry weight, number of flowers per plant, yield of dried flowers, essential oil content, potassium percentage, carbohydrate content, total chlorophyll, carotenoids and proline. Data analysis of variance was performed using SAS software and version 9.1. The mean of treatments was compared using Duncan's multiple range test at 5% level of probability.Results

The results showed that the effect of drought stress and potassium fertilizer on stem number, plant dry weight, number of flowers, carbohydrate and carotenoid content was significant. With increasing drought stress intensity to 50% FC, the number of stems and number of flowers per plant decreased by 36.08% and 39.57%, respectively, but with increasing drought stress intensity, the amount of carotenoids was 1.6 times that of non-stress treatment and the amount of carbohydrates 31.12% increase compared to non-stress treatment. The results showed that with increasing the amount of potassium fertilizer from 50 to 150 kg.ha-1, the number of stems and the concentration of carotenoids were 1.62 and 1.44 times, respectively, and the number of chamomile flowers per plant and the amount of carbohydrates were 30.52 and 41.20. Percentages increased. The results showed that plant height, dried flower yield, essential oil content, potassium percentage and proline were significantly affected by the interaction of drought stress and potassium fertilizer levels. With increasing stress intensity in all fertilizer treatments, a decrease in dried flower yield and an increase in proline content were observed. Application of potassium fertilizer had a significant positive effect on these traits under stress conditions so that by increasing the amount of potassium fertilizer from zero to 150 kg.ha-1 in severe drought stress plant height, dry flower yield, potassium and leaf proline, respectively. 2, 1.59, 2.64 and 1.95 times were control and the percentage of essential oil increased by 0.32%.

In general, it seems application of potassium within increase flower yield, can improve quantitative and qualitative traits of plant undser of drought stress, and decreased damages of drought stress

The most basic step in fruit tree breeding programs is the collection and evaluation of internal and external germplasm. The aim of this study was to evaluate the genetic diversity and grouping of the studied pear species based on 48 important quality traits of leaves, shoots, blossoms and fruits and to determine the genetic distance between them with identify cultivars suitable for cultivation and use them in breeding programs. Iran with more than ten species of pear and genetic diversity proximity centers to the product as an important source of genetic product is well-known in the world. Despite this privileged geographical location for pears in the country, so far, there is no accurate information about the genetic relationship between different pear genotypes in Iran, for the proper use of native genotypes for pear breeding purposes.

This study was conducted in 2018, with the evaluation of 13 pear species from eastern and western species in Karaj research institute for seed and seedling improvement and preparation of Lorestan university of horticultural sciences. In this study, three general traits of the tree, five traits of branches, 13 traits of leaves and petioles, six traits of blossoms and 20 traits of fruit were evaluated according to the national descriptor of differentiation, uniformity and stability (DUS) tests, which is a localized version of the international union for conservation of pear (UPOV) examination, uniformity and stability test instructions. In this study, cluster analysis was performed by Ward method.

The results of the evaluation of the studied traits showed that there was a high diversity in the characteristics of fruit size, the position of the largest fruit diameter, fruit shape, tip shape and leaf base among the studied species. In this study, cluster analysis was performed by Ward method using all the studied traits. The studied species were divided into three main groups at a distance of 400, so that Asian, native and European species were included in a separate group. The results of simple correlation of traits showed that leaf related traits such as length and width of the leaf had a positive correlation with the amount of fruit traits. Also, the highest negative and significant correlation was observed between the position traits of the largest fruit diameter and petal shape. The results of principal component analysis (PCA) showed, that the 11 main factors justify 97.99% of the total variance. Among the components, the first and second factors, which were mostly related to trunk strength, fruit and leaf traits, justified nearly 50% of the variance.

Based on the results, among the studied traits of fruit shape and size, leaf traits were the most important traits for detecting the diversity of pear species. This study showed that eastern and western pear species have significant diversity and are a valuable resource for plant breeding research.

Coronilla varia or Crownvetch is belonging to the Fabaceae family that is wildly distributed in different parts of Iran. The rapid spread of roots and shoots, as well as the ability to grow in stressful conditions, has caused it to be used to control soil erosion. In addition, the possibility of moving and regrowth has made Coronilla an appropriate alternative to turfgrass in green spaces. The aim of this study was to evaluate the response of Coronilla to freezing stress and the effect of glycine betaine on reducing seedling damage.

a factorial experiment was conducted in a completely randomized design with three replications. Low temperature for one hour in five levels [25 (control), 0, -5, -10 and -15°C] were used as the first factor and spraying with glycine betaine (one day before freezing stress) on two levels (0 and 100 mM) was considered as the second factor. After freezing stress, freezing injury, and physiological (relative water content, ion leakage) and biochemical (chlorophyll, proline, lipid peroxidation, protein, and peroxidase) attributes were measured.

According to the results, exposure to freezing temperatures (-10 and -15°C) increased the damage to Coronilla shoots. The absence of the difference between 0 and -5°C indicates that the temperature of -5°C is tolerable for the Coronilla. Foliar application of glycine betaine reduced leaf damage. The results showed that under freezing stress the relative water content of leaves and roots decreases. The lowest relative water content of leaf with 57.18% and 59.02% was related to severe stress at -10 and -15°C, respectively. Under freezing temperatures, the amount of ion leakage of roots and leaves increased, so that under severe stress of low temperature -15°C compared to 25°C, the amount of ion leakage of leaves increased by 27%. With decreasing temperature, the chlorophyll content of the leaves first increased at 0°C compared to 25°C, then decreased at temperatures below 0°C. While the use of glycine betaine (100 mM) increased the leaf chlorophyll content under freezing conditions. The results showed that with lowering temperatures, the amount of proline in leaf and root increased. In addition, foliar application of glycine betaine increased leaf proline by 7%. On the other hand, freezing stress led to a decrease in leaf (16%) and root (26%) protein at -10°C in Coronilla. In addition, compared to control with lowering the temperature, the high accumulation of malondialdehyde (leaf, 193%; root, 141%), and the activity of peroxidase enzyme in leaves (66%) and roots (156%) recorded.

Based on the results, it can be concluded that physiological and biochemical traits of Coronilla were affected by freezing stress. According to the results, leaf vulnerability was higher than the root. Low temperature caused damage to Coronilla by reducing the relative water content and ion leakage of leaves and roots. While spraying with 100 mM glycine betaine reduced the negative effects of freezing stress. Also, foliar application of glycine betaine effectively alleviates the adverse effects of freezing injury in Coronilla by increasing the accumulation of compatible osmolytes such as proline in leaves and roots.

Broccoli (Brassica Oleracea L.) is a winter season vegetable crop grown in many countries. Broccoli contains all the essential vitamins, mineral nutrients, amino acids and it has antioxidant and anticancer activity. Vegetables play a major role in daily human diet and they are required for maintaining of good health. Broccoli is one of the leading vegetables in the world. The selection of suitable planting dates and varieties is crucial for successful cultivation during rainy season. Fore this reasone, this experiment was performed to evaluate the effects of transplanting dates and broccoli varieties on their growth and yield.

This experiment carried out in 2017 - 2019 cropping seasons as split plot based on randomized complete block design with three replications in Rasht (Guilan province) climatic condition, Iran. Three transplanting dates (August 29, October 7 and November 15), four broccoli cultivars (Agassi RZ, Heraklion, Aquiles and Romanesco) comprised experimental treatments, as main and sub plot, respectively.

In this experiment, the effect of variety, transplanting date and the interaction effect between transplanting dates and variety was significant for all measured characteristics such as cordon weight, cordon yield, cordon diameter, plant height, leaf number per plant, leaf length and diameter and stem diameter. Results of this study showed that the highest cordon weight (800.82 g), cordon yield (33.36 t/ha), cordon diameter (31.42 cm), leaf length (57.06 cm) and diameter (26/69 cm) and stem diameter (6.30 cm) were obtained in Heraklion cultivar in response to August 29 transplanting date. But, greatest plant height (47.70 cm) and leaf number per plant (27.41) were observed in Aquiles cultivar and August 29 transplanting date. In addition, Romanesco broccoli after Heraklion cultivar showed superiority to other cultivars for all studied agronomic traits. There were positive and significant correlation between cordon yield and all measured characteristics including cordon weight, cordon yield, cordon diameter, plant height, leaf number per plant, leaf length and diameter and stem diameter.

In this experiment, delayed transplanting date, related to broccoli variety caused to a sever decrease in cordon yield. It seems that, delayed transplanting date could reduce cordon yield due to the decrease of plant photosynthesis capacity in broccoli plants. Hence, based on results of this experiment, early transplanting (August 29) after harvesting of rice crop and land preparation (second cropping) and Heraklion broccoli cultivar could be recommendable in order to enhance cordon yield per unit area under Guilan climatic condition.